Basic Construction

Abstract

To reduce the impact of building loads on underground structures. [Solution] The foundation structure 102 comprises a reinforced concrete foundation beam 120 supported by piles 50 and 51, and a steel truss 200 embedded in the reinforced concrete foundation beam 120 in a plan view, spanning the tunnel 90.

Description

Technical Field

[0001] The present invention relates to an infrastructure.

Background Art

[0002] Patent Document 1 discloses a technique related to a column base fixing structure using a steel-concrete foundation beam in a steel-frame building or the like. In the column base fixing structure using a steel-concrete foundation beam of this prior art, the end of a steel beam by a truss beam is joined to the side surface of the column base portion of a steel column, and a steel-concrete foundation beam is formed by this truss beam and the foundation concrete in which this truss beam is embedded, and the foundation concrete of this foundation beam is embedded around the column base portion of the steel column.

[0003] Patent Document 2 discloses a technique related to the structure of a steel-concrete foundation and a column. In this prior art, the column is divided into a lower column member embedded in the foundation concrete and an upper column member above it, and a joint plate is attached to the column using the space between flanges bolted together of these column members, and the end of a steel foundation beam is bolted to this joint plate to join the column and the steel foundation beam.

[0004] Patent Document 3 discloses a technique related to a joining structure of a precast column, particularly a steel column, when erecting it. The joining structure of the precast column and the footing of this prior art is formed by erecting a steel bridge pier on a load transfer plate and embedding this load transfer plate in concrete. The load transfer plate is configured by arranging I-shaped steels as steel beam members having flanges and webs in a lattice pattern such that their beam heights become the overall thickness. The load transfer plate is configured such that the member interval of the I-shaped steel is smaller in the central region than in the peripheral region, and a steel bridge pier can be erected near its center.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] When underground structures such as subway tunnels exist directly beneath a building, it is desirable to minimize the impact of the building's load on these underground structures.

[0007] In view of the above facts, the present invention aims to reduce the impact of building loads on underground structures. [Means for solving the problem]

[0008] The first embodiment is a foundation structure comprising a reinforced concrete foundation beam supported by a foundation, and a steel truss embedded in the reinforced concrete foundation beam, spanning underground utilities, in a plan view.

[0009] In the foundation structure of the first embodiment, the building load is distributed to both sides of the underground buried objects by the steel truss and acts from the foundation to the ground, thus reducing the impact of the building load on the underground buried objects.

[0010] The second embodiment is the foundation structure described in the first embodiment, wherein the foundation is a pile or isolated foundation arranged at intervals in the beam direction of the reinforced concrete foundation beam, and the pile or isolated foundation is arranged on both sides of the underground buried object in the beam direction in a plan view.

[0011] In the second embodiment of the foundation structure, since the piles or isolated foundations are positioned on both sides of the underground buried objects in a plan view, the influence of the building load acting on the ground from the piles or isolated foundations on the underground buried objects is further reduced.

[0012] The third embodiment is the foundation structure described in the second embodiment, wherein the spacing between the piles or independent foundations arranged on both sides of the underground buried structure in the beam direction is greater than the spacing between other parts.

[0013] In the third embodiment of the foundation structure, the deflection of the reinforced concrete foundation beam in areas where the spacing between foundations or isolated foundations is large is suppressed by the steel truss.

[0014] The fourth embodiment is a foundation structure according to any one of the first to third embodiments, wherein, in a plan view, multiple steel trusses are provided at intervals in an orthogonal direction perpendicular to the beam direction, and adjacent steel trusses are connected by pin joints of connecting members arranged along the orthogonal direction.

[0015] In the foundation structure of the fourth embodiment, the collapsing of the steel truss is prevented by connecting members.

[0016] The fifth embodiment is a foundation structure according to the first to fourth embodiments, wherein a ground-standing column is joined to the portion of the reinforced concrete foundation beam that straddles the underground buried object.

[0017] In the fifth embodiment of the foundation structure, the deflection of the reinforced concrete foundation beam due to the axial force of the standing columns is suppressed by the steel truss.

[0018] The sixth embodiment is a foundation structure according to any one of the first to fifth embodiments, wherein the foundation is made of piles, and the tip positions of the piles on both sides of the underground buried object are at a depth such that the underground buried object is above the 45° tip line.

[0019] In the sixth embodiment of the foundation structure, the impact of the building load acting from the piles on underground structures can be reduced. [Effects of the Invention]

[0020] According to the present invention, the impact of building loads on underground structures can be reduced. [Brief explanation of the drawing]

[0021] [Figure 1] It is an elevation view showing a schematic structure of a building to which the basic structure of one embodiment is applied. [Figure 2] It is an enlarged view of the main part structure of the basic structure part. [Figure 3] It is a perspective view of a steel frame truss and a connecting member. [Figure 4] It is a plan view of the schematic structure of the basic structure part. [Figure 5] It is a side view of the foundation pit. [Figure 6] It is an elevation view corresponding to FIG. 1 showing a schematic structure of a building to which the basic structure of the first modification example is applied. [Figure 7] It is an elevation view corresponding to FIG. 1 showing a schematic structure of a building to which the basic structure of the second modification example is applied.

Mode for Carrying Out the Invention

[0022] <Embodiment> The basic structure of this embodiment will be described. Here, two orthogonal horizontal directions are defined as the X direction and the Y direction, which are indicated by arrow X and arrow Y respectively. The vertical direction orthogonal to the X direction and the Y direction is defined as the Z direction, which is indicated by arrow Z.

[0023] Each drawing only shows schematically. Dimensions, ratios, etc. of each element shown in the drawing may not necessarily match the actual ones. Dimensions, ratios, numbers, etc. of each element may not necessarily match even between multiple drawings. In order to avoid being difficult to see, the hatching representing the cross section may be omitted. Also, descriptions of configurations not directly related to the present invention and well-known configurations may be omitted or simplified.

[0024] Figure 1 illustrates a building 10 to which the foundation structure 100 of this embodiment is applied. The building 10 of this embodiment has a ground floor 12 and a foundation structure section 102 to which the foundation structure 100 is applied. The ground floor 12 of this embodiment has a configuration having a high-rise section 14 and a low-rise section 16, but is not limited to this. The ground floor 12 of this embodiment is a reinforced concrete building with a rigid frame structure having columns 20 and beams 22, but is not limited to this.

[0025] Furthermore, a tunnel 90, which is an example of an underground utility, is constructed directly beneath the above-ground floor 12 of the building 10 in the ground G. In this embodiment, as shown in Figure 4, the tunnel 90 is constructed from the upper right to the lower left in a plan view, but is not limited to this.

[0026] As shown in Figure 1, the foundation structure 102 is constructed by being embedded in the ground G and consists of a reinforced concrete foundation beam section 110, a foundation slab 104 (see also Figures 2 and 5), and piles 50 and 51 as an example of a foundation. The space within the foundation structure 102 is referred to as the foundation pit 105 (see Figure 5).

[0027] As shown in Figures 1 and 4, piles 50 and 51 are positioned to avoid the tunnel 90 (see also Figure 4). Note that piles 50 are located on both sides of the tunnel 90 in the Y direction (see also Figures 2 and 4), while piles 51 cover the remaining areas. However, there is no difference between piles 50 and 51 other than their arrangement.

[0028] As shown in Figure 4, the reinforced concrete foundation beam section 110 is constructed by joining a reinforced concrete foundation beam 120 (see also Figure 2) aligned in the Y direction and a reinforced concrete foundation beam 130 aligned in the X direction in a grid pattern in plan view, on top of a reinforced concrete foundation slab 104 (see Figures 1 and 2). In Figure 4, the piles 50, 51 and the reinforced concrete foundation beams 120 and 130 are shown with dashed lines, while the steel truss 200 and connecting members 210, which will be described later, are shown with solid lines. Although not shown, the reinforced concrete foundation beams 120 and 130 have main beam reinforcement at their upper and lower ends, and shear reinforcement is placed around the main beam reinforcement. Similarly, although not shown, the reinforced concrete foundation slab 104 has main slab reinforcement and slab distribution reinforcement at its upper and lower ends.

[0029] As shown in Figures 1 and 4, piles 50 and 51 are constructed below the joint between reinforced concrete foundation beam 120 and reinforced concrete foundation beam 130 (see also Figures 2 and 5). Footings 106 are constructed above piles 50 and 51 (see also Figure 5). In this embodiment, an intermediate slab 18 is constructed in the foundation pit 105 (see Figure 5) along the Y direction. The intermediate slab 18 connects adjacent footings 106 in the Y direction. Note that the intermediate slab 18 does not necessarily have to be constructed.

[0030] As shown in Figures 1 to 4, a steel truss 200 is embedded in the reinforced concrete foundation beam 120 along the Y direction. As shown in Figures 2 and 3, the steel truss 200 in this embodiment is a steel member of a truss structure composed of an upper chord 202, a lower chord 204, a support member 206, and a diagonal member 208. In Figure 2, for clarity, the embedded steel truss 200 within the reinforced concrete foundation beam 120 is shown with a solid line. The portion of the reinforced concrete foundation beam 120 in which the steel truss 200 is embedded is referred to as the steel-reinforced concrete section 121.

[0031] As shown in Figures 1, 2, and 4, the steel truss 200 is partially embedded in each reinforced concrete foundation beam 120 in a plan view, in the portion that straddles the tunnel 90 (see Figures 1 and 4). From another perspective, the steel truss 200 is embedded only in the portion of the reinforced concrete foundation beam 120 that straddles the tunnel 90 (see Figures 1 and 4) along the Y direction. The X-direction end of each steel truss 200 is located slightly outside the X-direction of the tunnel 90 (see Figures 1 and 2) in a plan view. In addition, a footing 106 (see Figures 1 and 2) and a pile 50 (see Figures 1 and 2) are positioned below the X-direction end of each steel truss 200.

[0032] As shown in Figure 1, piles 50 and 51 are spaced apart in the Y direction, which is the beam direction of the reinforced concrete foundation beam 120. As mentioned above, piles 50 are positioned on both sides of the tunnel 90 in the beam direction in a plan view, avoiding the tunnel 90. The Y-direction spacing L1 of piles 50 on both sides of tunnel 90 is wider than the L2 of piles 50 and 51 in other areas. Note that the spacing L2 is the same in the figure, but it is not limited to this. The largest possible Y-direction spacing L1 of piles 50 is desirable.

[0033] The tip position 50S of pile 50 is at a depth where the tunnel 90 is above the tip 45° line V. The tip 45° line V is a line drawn at a 45° angle diagonally downwards from the tip position 50S of pile 50.

[0034] As mentioned above, the steel trusses 200 shown in Figure 4 are embedded in each of the reinforced concrete foundation beams 120 along the Y direction, straddling the tunnel 90. In other words, as shown in Figures 3 and 4, in a plan view, multiple steel trusses 200 are provided at intervals in the X direction, which is perpendicular to the Y direction, which is the beam direction. Adjacent steel trusses 200 are connected by connecting members 210 made of steel members arranged along the X direction. The steel trusses 200 and the connecting members 210 are bolted together, so they are pin-jointed. As shown in Figure 4, in this embodiment, the connecting members 210 connect the joints between the upper chord members 202 and the support members 206, and between the joints between the lower chord members 204 and the support members 206. As shown in Figure 4, the connecting members 210 are embedded in the reinforced concrete foundation beams 130 along the X direction.

[0035] Furthermore, as shown in Figures 1 and 2, in this embodiment, the column 20A joined to the portion of the reinforced concrete foundation beam 120 that straddles the tunnel 90 (see Figure 1), that is, the portion between the piles 50, is a ground-standing column without a pile 50 directly below it.

[0036] [Effect] Next, the operation of this embodiment will be described.

[0037] The building load of building 10 is transmitted to the ground G mainly from piles 50 and 51 of the foundation structure 102. At this time, the building load acting on the steel-reinforced concrete section 121, which is the part of the reinforced concrete foundation beam 120 along the Y direction in which the steel truss 200 is embedded, flows to both ends of the steel-reinforced concrete section 121 in the Y direction, and from both ends flows to the piles 50 via the footing 106 and is transmitted to the ground G. The piles 50 are not directly above the tunnel 90, but are located on both sides of the tunnel 90 in the Y direction. Therefore, compared to the case where the piles 50 are directly above the tunnel 90, the influence of the building load transmitted from the piles 50 to the ground G on the tunnel 90 is reduced. The influence of the building load transmitted to the ground G on the tunnel 90 is, for example, the possibility that the tunnel 90 may settle or deform due to the building load transmitted to the ground G.

[0038] Furthermore, the tip positions 50S of the piles 50 on both sides of the tunnel 90 are at a depth where the tunnel 90 is above the tip 45° line V. Below this tip 45° line V, the influence of the building load transmitted from the piles 50 to the ground G becomes greater. Therefore, compared to the case where the tunnel 90 is below the tip 45° line V, the influence of the building load transmitted from the piles 50 to the ground G on the tunnel 90 becomes smaller. The tip 45° line is defined as the range where the influence of the building load transmitted from the piles to the ground is greatest.

[0039] Furthermore, since the piles 50 are positioned on both sides of the tunnel 90 in the beam direction in a plan view, avoiding the tunnel 90, the Y-direction spacing L1 of the piles 50 on both sides of the tunnel 90 is greater than the Y-direction spacing L2 of the piles 51 in other parts. In the areas of the reinforced concrete foundation beam 120 where the spacing L1 of the piles 50 is large, the steel truss 200 is partially embedded, increasing its rigidity. Therefore, even in areas where the spacing L1 of the piles 50 supporting the reinforced concrete foundation beam 120 is large, deflection is suppressed by the steel truss 200.

[0040] Furthermore, since there is no pile 50 directly beneath column 20A, which is joined to the reinforced concrete foundation beam 120 at the point where it straddles the tunnel 90, it is a ground-standing column. As mentioned above, a steel truss 200 is partially embedded in the area where column 20A, which is a ground-standing column in the reinforced concrete foundation beam 120, is joined, thereby increasing its rigidity. Therefore, even in the area where column 20A, which is a ground-standing column in the reinforced concrete foundation beam 120, is joined, deflection is suppressed by the steel truss 200.

[0041] Furthermore, multiple steel trusses 200 are provided at intervals in the X direction, which is perpendicular to the Y direction, which is the beam direction of the reinforced concrete foundation beam 120. Adjacent steel trusses 200 are connected by connecting members 210 arranged along the X direction, which are pin-jointed. Thus, the connecting members 210 prevent the steel trusses 200 from collapsing.

[0042] Furthermore, in this embodiment, an intermediate slab 18 is constructed along the Y direction, connecting adjacent footings 106 in the Y direction. Therefore, during an earthquake, the intermediate slab 18 bears a portion of the seismic force in the Y direction. The beam depth of the reinforced concrete foundation beams 120 and 130 in this embodiment is several meters, for example, about 4.5m. Therefore, the intermediate slab 18 is also used as a catwalk for workers performing tasks in the foundation pit 105.

[0043] <Variation> Next, a modified example of this embodiment will be described. In the modified example, the same reference numerals are used for the same components as in the above embodiment, and redundant explanations are omitted.

[0044] [First variation] In the first modified example foundation structure 103 shown in Figure 6, there are no piles 50 and 51, and the building load is mainly transmitted to the ground G from the foundation and footing 106, which is an example of an isolated foundation.

[0045] The building load acting on the steel-reinforced concrete section 121, which is the part of the reinforced concrete foundation beam 120 along the Y direction in which the steel truss 200 is embedded, flows to both ends of the steel-reinforced concrete section 121 in the Y direction and is transmitted from both ends to the ground G via the footing 106. The footing 106 is not directly above the tunnel 90, but is located on both sides of the tunnel 90 in the Y direction. Therefore, compared to the case where the footing 106 is directly above the tunnel 90, the influence of the building load transmitted from the footing 106 to the ground G on the tunnel 90 is reduced.

[0046] In this modified example, it is desirable that the tunnel 90, as an example of an underground structure, be located lower than shown in the diagram, as this greatly reduces the effect of the building load on the tunnel 90. Furthermore, in this modified example, increasing the distance between the tunnel 90 and the foundation structure 103 reduces the effect of the building load on the tunnel 90 more effectively than the effect of the building load on the tunnel 90 due to the piles 50 in the foundation structure 102 of the above construction configuration.

[0047] Furthermore, compared to the reduction of the building load's influence on the tunnel 90 by the piles 50 in this embodiment, the influence of the building load can be reduced by increasing the distance between the tunnel 90 and the foundation structure 102.

[0048] [Second variation] In the second modified example foundation structure 107 shown in Figure 7, there are no piles 50, 51 and footing 106. However, a foundation slab 104 is not provided directly above the tunnel 90. Specifically, a foundation slab 104 is provided in area WA, but a foundation slab 104 is not provided in area WB, and only lean concrete is present.

[0049] Therefore, the building load acting on the steel-reinforced concrete section 121, where the steel truss 200 is embedded in the reinforced concrete foundation beam 120, flows to the foundation slabs 104 at both ends of the steel-reinforced concrete section 121 in the Y direction and is transmitted to the ground G. The area to which the building load is transmitted is between lines KA in the ground G. Consequently, compared to the case where the steel truss 200 is not embedded, the influence of the building load transmitted from the foundation slabs 104 to the ground G on the tunnel 90 is reduced.

[0050] In this modified example, it is desirable that the tunnel 90, as an example of an underground structure, be located lower than shown in the diagram, within the area where the building load is transmitted, as this greatly reduces the effect of the building load on the tunnel 90. Furthermore, in this modified example, increasing the distance between the tunnel 90 and the foundation structure 107 reduces the effect of the building load on the tunnel 90 more effectively than the effect of the building load on the tunnel 90 due to the piles 50 in the foundation structure 102 of the above construction configuration.

[0051] <Other> However, the present invention is not limited to the embodiments and modifications described above.

[0052] For example, in the above embodiments and modifications, the underground structure was a tunnel 90 on which a subway train runs, but it is not limited to this. It may also be a tunnel on which an electric train runs, or a utility tunnel, drainage pipes for equipment, gas pipes, trenches, water tanks, concrete rubble, etc.

[0053] Furthermore, the present invention can be implemented in various forms without departing from the spirit of the invention. Multiple embodiments and modifications can be combined as appropriate. [Explanation of Symbols]

[0054] 10 Buildings 50 Piles (Example of a foundation) 50S tip position 51. Stakes (an example of a stake) 90. Tunnels (an example of underground structures) 100 Basic structure 103 Basic structure 104 Foundation slab (an example of a foundation) 106 Footing (an example of a foundation and isolated foundation) 107 Basic structure 120 Reinforced concrete foundation beam 200 Steel Truss 210 Connecting material

Claims

1. Reinforced concrete foundation beams supported by the foundation, In a plan view, the steel truss embedded in the reinforced concrete foundation beam, spanning underground buried structures, A foundation structure equipped with these features.

2. The aforementioned foundation consists of piles or isolated foundations arranged at intervals in the beam direction of the reinforced concrete foundation beam. The piles or the independent foundations are arranged on both sides of the underground structure in the beam direction in a plan view. The foundation structure according to claim 1.

3. The spacing between the piles or independent foundations located on both sides of the underground structure in the beam direction is greater than the spacing between other parts. The foundation structure according to claim 2.

4. In a plan view, multiple steel trusses are provided at intervals in a direction perpendicular to the beam direction. Adjacent steel trusses are connected by pin joints of connecting members arranged along the orthogonal direction. The foundation structure according to claim 1.

5. A standing column is attached to the portion of the reinforced concrete foundation beam that straddles the underground buried structure. The foundation structure according to claim 1.

6. The aforementioned foundation consists of piles. The tip positions of the piles on both sides of the underground structure are at a depth where the underground structure is above the 45° tip line. The foundation structure according to claim 1.

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